Nanolayered Au/Ti/Al Ohmic Contacts to P-Type SiC: Electrical, Morphological and Chemical Properties Depending on the Contact Composition

摘要

Electrical, morphological and chemical properties of nanolayered Au/Ti/Al ohmic contacts with different Ti:Al ratio are investigated. Contact resistivities of 1.42×10~(-5) Ω·cm~2 and 1.2×10~(-5) Ω·cm~2 are achieved for Au/Ti(70)/Al(30) and Au/Ti(30)/Al(70) contacts, respectively. It is found that the Ti:Al ratio does not affect the lowest resistivity value but influences on the optimal annealing temperature at which it is obtained. The different optimal annealing temperature provokes different element distributions and interface chemistry of the annealed contacts. An increase of the Al concentration in the contact composition causes essentially the surface morphology leading to an increase in surface roughness of the as-deposited and annealed contacts.